1. Field of the Invention
This invention relates generally to a water filter cartridge for use in a water filtration system. The water filter cartridge may be used for example to treat microorganism contaminated water so as to provide water suitable for drinking. More particularly, the invention relates to a replaceable water filter cartridge for use in a refrigerator filtration system having an easily removable, circumferential basket seal that presents sealing surfaces in the radial and axial directions for interfacing with a manifold cylindrical port and bayonet locking scheme.
2. Description of Related Art
In recent years, as the public has begun to realize the benefits derived from drinking highly pure water, there has been a great increase in the sale and availability of household water filtration devices. Concurrently, refrigerator mounted water dispensers and automatic ice makers have become more commonplace. In response to this fact, water filters have been incorporated within household refrigerators to provide a filtered water supply for direct dispensing via the refrigerator water dispenser, or for use in making ice cubes via an automatic ice maker.
A typical residential water filtration system generally includes a distribution manifold configured to accept a prepackaged cartridge filter. The distribution manifold is typically adapted to connect either directly or indirectly to a residential water supply and to points of use, and may even allow for a drain connection. Generally, the prepackaged cartridge filter sealingly engages the distribution manifold such that an inlet flow channel connecting the residential water supply and the cartridge filter is defined, and at least one outlet flow channel connecting the cartridge filter and the points of use is defined.
It is common for refrigerators to have a water dispenser disposed in the door and in fluid communication with a source of water and a filter for filtering the water. Further, it is common for refrigerators to have an ice dispenser in the door and be in fluid communication with a source of water and a filter for filtering the water. Like the filters installed in a water purifier device, the filter installed in a refrigerator is degraded in its purification capabilities when it is used for a certain period of time. Thus, the filter installed in the refrigerator is periodically required to be changed for a new filter according to its lifespan. Replaceable filter cartridges require circumferential sealing with the manifold port in order to ensure a leak proof interface, especially when the filter-manifold combination is designed to remain unchecked for a considerable amount of time. The seals on the manifold cylindrical ingress and egress bayonet ports are generally not replaced when a new filter cartridge is installed, and over time these port seals have been shown to degrade and cause leakage. Consequently, the seal on the replaceable filter cartridge becomes integral to the integrity of the manifold-filter cartridge watertight bond. In some refrigerator water filtration systems, as a cost saving measure, the only seals for ensuring a water-tight bond are placed on the manifold bayonet ports, and thus the water filtration systems are more prone to leakage as these manifold port seals are exercised with each replacement cartridge installation. Rotational forces on the manifold port seals, which may vary depending upon variances in the complementary diameters of the manifold port and the filter cartridge receiving recess port, may be detrimental to the seal integrity yet unknown for a period of time to the user.
One such refrigerator water filtration system is disclosed in U.S. Pat. No. 5,753,107 issued to Magnusson, et al., titled “DRIPLESS PURIFICATION MANIFOLD AND CARTRIDGE.” The filter cartridge is located in the interior of the refrigerator and mates with a manifold using a bayonet locking scheme. The preferred filter cartridges used with, and designed for, the manifold of the Magnusson design do not have any circumferential seals, such as O-rings, located adjacent their mating surfaces, and therefore the prevention of leaks in the water filtration system is totally dependent on the integrity of the O-rings that are placed on, and circumferentially surround, the male cylindrical bodies of the manifold. FIG. 1 depicts a general prior art manifold for receiving the filter cartridge of the present invention.
A filter cartridge for the Magnusson design is identified in U.S. Pat. No. 6,027,644 which issued to Magnusson, et al., on Feb. 22, 2000. This cartridge supports a bayonet fitting and the appurtenant O-rings to a seal free two stage recess, which arguably simplifies the construction of the cartridge versus “conventional” cartridges having bayonet fittings and circumferential O-rings. The conventional cartridges are known to provide generally a circumferentially sealed bayonet fitting which mates to a recess or pair of recesses at the manifold. In this manner, a large number of relatively costly O-ring seals are thus required to accommodate the disposable cartridges. The Magnusson system avoids the cost by mounting on the manifold ingress and egress ports the only seals used for securing a water-tight bond. However, over time, the manifold O-ring seals at the filter cartridge interface will degrade, and their sealing efficiency potentially compromised under rotational insertion forces with each introduction of new, replaceable, seal free filter cartridges.
Some replacement filter cartridges have included an additional O-ring mounted in the large female cylindrical cavity of the filter cartridge to provide additional sealing capability; however, the location of this O-ring seal makes it prone to movement and misalignment during installation.